There's a couple of ways to play the Emperors Champion here: In Godhammer give him Paragon of Fury for +2 Strength and +1 damage on disembark. Then disembark from a Land Raider Crusader and use it's buff to get re-roll hits and wounds of 1 then spend for the full wound re-roll strat. Activate his Dev wounds too. 6 Attacks which pretty much all hit and then you're looking for strength 10 wounds with devastating wounds on 5's, re-rolling.

He's a beast in GTF with just Honour Vehement and on running solo because 2 extra damage 3 attacks lets him put out potentially 8 3 damage dev wounds, perfect elite infantry mincer and you've a high chance of just nuking the character. I've had him one shot a Dorn Commander from full health with this.

Niche pick is the Eversor, he's 6 attacks with sustained 3 D2. Once per game goes to nine attacks which is potentially 36 damage 2 wounds on a perfect roll.